Joseph Prudell

A Permanent-Magnet Tubular Linear Generator for Ocean Wave Energy Conversion

This paper presents a novel permanent-magnet tubular linear generator (PMTLG) buoy system designed to convert the linear motion of ocean waves into electrical energy. The design incorporates no working seals and a saltwater air-gap bearing surface integration between the PMTLG buoy components. The internal generator design will be discussed, in addition to the system integration with the buoy structure. The simulation and hardware results of the generator are presented.

Comparison of Direct-Drive Power Takeoff Systems for Ocean Wave Energy Applications

This paper presents a comprehensive power takeoff (PTO) analysis program conducted as a collaborative research effort between Columbia Power Technologies, Inc., Oregon State University (OSU), and the U.S. Navy. Eighteen different direct-drive technologies were evaluated analytically and down-selected to five promising designs. Each of the five prototypes was simulated, modeled in SolidWorks, and built at the 200-W peak level and tested on OSUs wave energy linear test bed. The simulations were validated with the 200-W experimental results and then scaled up to 100 kW, with full 100-kW designs including costs, maintenance, operations, etc., to estimate the cost of energy (COE) for each PTO buoy system at utility scale.

Scaled Development of a Novel Wave Energy Converter Including Numerical Analysis and High-Resolution Tank Testing

This paper presents the scaled development of a novel point absorber wave energy converter (WEC) developed by Columbia Power Technologies (COLUMBIA POWER, Corvallis, OR, USA), including numerical analysis and scaled wave tank testing. Four hydrodynamic modeling tools are employed to evaluate and optimize the performance of the WEC, including WAMIT, Garrad Hassans GH WaveDyne, OrcaFlex, and ANSYS AQWA. Performance and mooring estimates at full scale are evaluated and optimized, followed by the development of 1 : 33, 1 : 15, and 1 : 7 scale physical models. The physical tests of the 1 : 33 and 1 : 15 scale WECs were conducted in the wave basins of Oregon State Universitys O.H. Hinsdale Wave Research Laboratory, in conjunction with the Northwest National Marine Renewable Energy Center (NNMREC). This paper concludes with the development of the 1 : 7 scale WEC and the associated field testing.

WEC prototype advancement with consideration of a real-time damage accumulation algorithm

Machine maintenance and repair is not a trivial issue when it comes to renewable energy devices. It has been said that one of the most important factors in enhancing the marketability of wind energy is to cut its overall maintenance costs, which is about 10% – 20% of the overall cost of energy [1]. The average maintenance and repair costs of ocean wave energy devices are yet to be determined, but it may be higher than wind energy. The harsh ocean environment, repeated cycling of the drive train, coastal storms, environmental concerns, loss of revenue due to long periods of machine downtime, safety issues concerning technicians working on the buoy while its still in operation, and so forth, all add to the maintenance and repair costs of a WEC (Wave Energy Converter). This study proposes a unique damage accumulation prediction algorithm that enables real-time determination of bearing fatigue life.

Scaled development of a novel Wave Energy Converter through wave tank to utility-scale laboratory testing

This paper presents the scaled development of a novel point absorber Wave Energy Converter (WEC) developed by Columbia Power Technologies, Inc. (CPwr), including scaled wave tank testing to utility-scale laboratory testing. The scaled development and testing of 1:33, 1:15 and 1:7 scale physical models are discussed. The physical tests of the 1:33 and 1:15 scale WECs were conducted in the wave basins of Oregon State Universitys O.H. Hinsdale Wave Research Laboratory, in conjunction with the Northwest National Marine Renewable Energy Center (NNMREC). The 1:7 scale WEC was field tested for 13 months in Puget Sound, WA. This paper concludes with the development of the utility-scale WEC and the associated laboratory testing on the National Renewable Energy Laboratory (NREL) Wind Technology Center dynamometer test bed.

IEEE standards for oscillating machines to advance direct-drive wave energy generators

The objective of this paper is to present the need for IEEE standards for oscillating machines employed in wave energy generators. Due to the oscillating motion of ocean waves, the wave energy generator profiles are highly non-periodic and stochastic. Currently there are no IEEE or IEC standards for these types of oscillating machines, and thus critical questions remain unanswered such as the nameplate ratings and efficiencies that should be targeted for cost effective operation. Oscillating operation in an ocean environment is presented in the paper including real-world speed, torque, and output power testing data from an ocean wave energy generator. Related standards are discussed to illustrate that the duty types are not suitable to describe and represent the oscillating motion of wave energy generators. The paper concludes with an example utility-scale wave energy converter (WEC) design including the demanding cyclic operating conditions, and then presents required standards.

Direct drive ocean wave energy electric plant design methodology

Conversion of power from ocean waves requires power take off systems which are designed to accommodate a wide range of power variations. Power smoothing has traditionally been designed into the primary mechanical power conversion process. With a direct drive design, power smoothing is achieved by power electronics. The following paper presents a comprehensive analysis of the system requirements and design philosophy for the electric plant of a direct drive ocean wave energy converter (WEC). Annual real seas data was used to model power flow from rotary Permanent Magnet Generators (PMG) through the electric plant to the grid. Component pricing and site specific wave climates are incorporated into simulations to guide the electric plant design development. The results of these simulations provide design recommendations on WEC electric plant configuration and component specification for the lowest capital cost and high energy production.

Direct Drive Wave Energy Buoy

Presentation from the 2011 Water Peer Review in which principal investigator discusses project progress and results for this project which will be used to inform the utility-scale design process, improve cost estimates, accurately forecast energy production and to observe system operation and survivability.

Direct Drive Wave Energy Buoy – 33rd scale experiment

Columbia Power Technologies (ColPwr) and Oregon State University (OSU) jointly conducted a series of tests in the Tsunami Wave Basin (TWB) at the O.H. Hinsdale Wave Research Laboratory (HWRL). These tests were run between November 2010 and February 2011. Models at 33rd scale representing Columbia Power’s Manta series Wave Energy Converter (WEC) were moored in configurations of one, three and five WEC arrays, with both regular waves and irregular seas generated. The primary research interest of ColPwr is the characterization of WEC response. The WEC response will be investigated with respect to power performance, range of motion and generator torque/speed statistics. The experimental results will be used to validate a numerical model. The primary research interests of OSU include an investigation into the effects of the WEC arrays on the near- and far-field wave propagation. This report focuses on the characterization of the response of a single WEC in isolation. To facilitate understanding of the commercial scale WEC, results will be presented as full scale equivalents.